Free-standing urchin-like nanoarchitectures of Co3O4 for advanced energy storage applications

A potential electrode material, besides the higher specific capacitance, should also exhibit superior cyclic stability and good rate capability. Here, we have fabricated urchin-like hierarchical Co3O4 nanoarchitecture directly on the Ni-foam (NF) by a scalable hydrothermal and post-sintering treatment. The as-fabricated Co3O4/NF electrode shows higher pseudocapacitance (PSCs) of 848 Fg−1 (at1 Ag−1) and good rate capability as it retains 84.6% of its initial PSCs (at 1 Ag−1) at 10 Ag−1. Furthermore, fabricated Co3O4/NF electrode also exhibits superior cyclic performance as it holds 95.7% of its initial PSCs after 5000 CV tests. The outstanding percentage coulombic efficiency of 99.1% at 10 Ag−1 also confirms the feasibility and cyclic-reversibility of the Faradic reaction. The observed superior capacitive behavior of Co3O4/NF electrode is accredited to its binder-free design, uniform architecture, and urchin-like open structure. These observed electrochemical results suggest that Ni-foam supported urchin-like hierarchical Co3O4 nanoarchitecture is the promising electrode material for high-performance hybrid supercapacitors applications.